Knife-blade switch.



- AJK. SUTHERLAND.

KNIFE BLADE SWITCH.

APPLICATION'FILED NOV-26.19M-

1, 16,513. Pat ente d Feb. 20,1917.

WITNESS U IIVLIEIVTOR I ATTORNEY wll dtl ld reta ner in.

ALEXANDER K. SUTHERLAND, OF PLAINVILLE, CONNECTICUT, .ASSIGNOR TO THE TRUMB'ULL ELECTRIC MANUFACTURING COMPANY, 9F PLAINVILLE, CONNECTICUT,

A CORPORATION OF CONNECTICUT.

KNIFE-BLADE SWITCH.

Specification of Letters Patent.

Patented Feb. 241, 1917.

Application filed November 26, 1915. Serial No. 63,376.

lliis invention relates to knife blade switches and has for its object to provide locking means which will retain the. blade or blades in any predetermined position or positions, my novel locking'means being especially useful in connection with doublethrow switches having contact jaws both above and below the plane of the pivot, as it obviates the danger of the blades becoming disengaged from a pair of higher jaws and dropping down into contactwvith a pair of lower jaw-s in case of jarring, or loosening of the spring washers should they be used. It has been the common practice in this class of switches to set up the spring Washers with considerable pressure in order to retain the blade in an intermediate position when the circuits were open, or to prevent the bladc from dropping out of engagement 'withone pair of contact jaws and into engagement with a lower pair of contact jaws, as in switches used for reversing the circuit or for changing from local to city circuit, or from alternating to direct current and vice versa. This tightening up of spring Washers has been found seriously objectionable for the reason that when the blade was gripped tightly enough by the ears to retain it in any required position, the metal would out? My present invention wholly does away with this dilliculty.

With these and other objects'in view, I have devised the novel blade-locking device,

which I will now describe, referring to the accompanying drawing forming a part of this specification, and using reference characters to indicate the several parts.

Figure 1 is a side elevation of a doublepole double-thrmv switch with my novel locking means applied thereto;

Fig. 2 a plan viewcorresponding therewith;

Fig. 3 a detail elevation scale;

Fig. 4 a plan view corresponding therelyitl'lp Fig. 5 a perspective View on the scale of on an enlarged Figs. 1 and 2 showing the invention applied to a multi-circuit switch having pairs of contact jaws of different heights, and

Fig. (5 is a detail elevation on the scale of Fig. 3, showing a \arianfiforn oi the invention. i

10 denotes a base, of insulating material.

"11 pairs of contact jaws seen red thereto, 12

holding pieces, 13 blades, I i an insulating cross "piece. and 15 a handle which in doublepole switches is secured lo the cross piece and in single-pole switches", by a suitable insulating connection, to tlre--l1l.:.1dc. The contact jaws and the. holding pieces are rigidly secured to the base in any ordinary or preferred manner. The holding pieces are provided with cars 16 between which the inner'ends oi the blades are secured by pivot bolts 17. The pivot bolts may or may not be provided with spring washers 18, adapted to be set up against one. of the cars by a nut 19. use or non-use of s 'n'ing wasl'iers is wholly immaterial so far as the present invention is concerned.

My present invention consists in providing the blades and the. holding pieces with intorengaging means which lock the blades at required positions. For example, I provide the blades with pins 20 and provide upon the hohling pieces spring keepers 21 with which the pins are adapted to engage. The, keepers are plates of spring metal each having a hole through which the pivot boltpasses and at its inner end a lug adapted to be turned into a hole 23 Ill the holding piece to lock the keeper against movement with the blade. Each keeper is provided on its inner lace, at the outer end, with a groove 24. which is adapted to receive the pin, and at its edges with inclines 25, which are,adapted to be engaged by the pin, a pin. when it engages an incline, riding up the incline and springing the keeper backward until the pin engages the groove, which locks the blade yieldingly in place. The tension of the keeper is sullicicnt to retain the blade in position against jarring 0" any oi the conditions of use, but yields when a moderate amount of power is applied to the handle.

In Figs. 1 to 4 inclusive, the keeper and pin are so arranged as to lock the blade in its intermediate or upright position.

- it should be understood that the In Fig. 5, I haveshown the invention as applied to a type of switch having a plurality of pairs of contact jaws of different heights so that when the blade is swungdownward it will engage first one pair of jaws, then another, and then another. The keeper inthis form is made sector-shaped, and is provided with a p111 'ality of radial grooves, one being adapted to lock the blade in-its upright position, and the others to lock it in successive positions as it comes into engagement with Successive pairs of contact jaws. The opel -ation is the same as before, the only difference being duplication of pairs of contact jaws and corresponding locking grooves in the keeper.

In Fig.6, I have illustrated a variant rforni adapted for use with two pairs of contactjaws'. In this form the keeper, instead of heme; set ,in ahneinentwith the holding piece, is set obliquely thereon and the blade,

instead of having one pin located centrally,

position. Xo locking means is required in connection with the last pair of locking jaws in a series, as it makes no difference how far the blade passes in between the jaws.

Having thus described my invention, I claim i 1. In a switch of the character described, a holding piece, a blade pivoted to the holding piece and provided with a pin, and a spring keeper secured to the holding piece and having at its outer end a groove adapted to receive and yieldinglv engage the pin and at its edges inclines against which the pin acts to spring the keeper backward until the pin reaches said groove.

2. In a knife blade switch, a holding piece having ahole, a blade pivoted to the holding piece and provided with a pin, and

a keeper removably secured to theholding piece and having at its inner end a. lug engaging the hole, at its outer end a groove adapted to receive the pin and at its edges inclines adapted to be engaged by, the pin to spring the keeper backward until the pin engages the groove.

In testimony whereof I atlix my signature.

ALEXANDER K. SUTI-IERLAND. 

